Transmission synchronizer



Oct. 10, 1939 J. M. SIMPSON TRANSMISSION sYNcHRoNIzER Filed Feb. 20, 1957 rz/YJ Patented Oct; 10, 1939 UNITED i STATES TRANSMISSION SYNCHRONIZER John M. Simpson, Muncie, Ind., assignor to Borg- Warner Corporation, Chicago, 111., a corporation of Illinois Application February 20, 1937, Serial No. 126,764

2 Claims.

This invention relates to improvements in transmission synchronizers of the type which may be used to synchronize the speed-changing gear mechanism of a motor vehicle transmission.

An object of this invention is to provide an improved transmission synchronizer.

Another object is to provide a transmission synchronizer which occupies relatively small space along its longitudinal axis.

Other objects and advantages will become apparent after reading the following description and claims.

An embodiment of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 is a side elevation of a change speed unit, the upper half being broken away and in section to show theapplication of my invention;

Fig. 2 is a sectional view on the line 2--2 of Fig. 1, and

Fig. 3 is a top plan view of a part of the mechanism illustrated in Figs. 1 and 2.

Referring to the drawing, 3 represents the drive shaft of a motor vehicle transmission, 4 the intermediate or driven shaft, and 5 the countershaft. The intermediate shaft 4 may be piloted, as indicated at 5, in the shaft 3. A gear I on the shaft 3 meshes with a spur gear 8 on the countershaft 5, and-a spur gear 9 on the countershaft 5 is in mesh with a second speed gear l2. The gear l2 rotates in floating relationship upon-the intermediate shaft 4. Mounted on the intermediate shaft 4 between the drive gear I and the second speed gear I2 is a shiftable member 22 having on each of its sides and integral therewith clutch members 25 and 28, respectively, each formed with teeth indicated respectively at 26. and 29, said member 22 being slidably splined to the shaft 4 as shown. An annular groove il may be formed in the member 22 in which is adapted to fit the shift fork 22 of a gear shift rail 24.

Assembled with the shiftable member 22 and located within the grooves of the splines 34 of the shaft 4 are spring fingers l5 having detents 32 and 33 which yieldably block the right and left movement of the shift member 22 with its clutch members 25 and 25 from. amid-way position between the friction discs I! and i4.

These spring members l5, three in number, are spaced equidistantly around the shaft 4 as may be seen in detail in Fig. 2. Y

Secured to the opposite extremities of the spring members I! and also slidably splined to the intermediate shaft 4. and in register respectively with the drive gear 1 and the second gear i2, arefriction discs i3 and i4 having conical friction faces l6 and Ill-adapted to engage the spur teeth I1 and 2!, respectively, of the gears 1 and I2.

The teeth I! of the, spur gear "I, which mesh with the teeth of spur gear 8 on the countershaft 5, have a portion of their outer surfaces shaped to closely receive the inner conical surface of the friction face iii of the friction cone l3 so that by pressure of the friction face ii on the teeth I! the drive shaft 3 may cause the shafts 3 and 4 to be synchronized as to speed.

On the gear 1 opposite and aligned with the jaw teeth 26 of 'clutch member 25 are fixed jaw teeth 21 adapted to be engaged with the teeth 26 of slidable clutch member .25 to give positive clutch action.

The second speed gear l2, like the gear 1,-has spur teeth 2| coned at one end to engage the friction surface I9 of the disc l4 and jaw clutch teeth 3i adapted to be engaged with the teeth v against the teeth I! through the instrumentality of the springs l5. This movement of the disc I3, which causes engagement between the cone I5 and its complementary portion of the gear teeth l'l', also causes synchronization of the shafts 3 'and 4 to take place. Further movement of the shiftable member 22 results in the depression of detent 32, thereby to permit the jaw teeth 26 of the disc l3 and to engage with the jaw teeth 21 of the gear I, thus to produce a positive two-way drive.

By similar successive action of the friction clutch l$--2l and jaw tooth clutch 29-3l, synchronized second speed driving is effected, the

action in this case being accomplished by moving 'the shiftable member 22 in the opposite direction as will be apparent from the drawing.

By enlarging the discs l3 and M to a diameter greater than the diameter of the gears 1 and 12, respectively, and by providing for frictional enthe slidable clutch member 25 to pass through gagement between the friction cones carried at the peripheries of the discs and complementary conical surfaces formed directly upon the teeth area of contact between the frictionally engaging elements of the synchronizer clutches. This construction and arrangement manifestly will prolong the useful life of the synchronizer which must necessarily be subjected to wear by the inherent nature of its function. Furthermore, the construction and arrangement described herein permits of a more compact high and second gear synchromesh assembly for the reason that the synchronizing cones actually embrace the outer peripherial or tooth portions of the high and second speed gears, and the jaw clutch element, being contained within the periphery of the gear, adds nothing to the width thereof. This contributes to axial compactness. Obviously, the same arrangement may be carried out in connection wth any of the adjacent elements of a transmission gear train where synchronization is desirable.

I claim:

1. A synchronizing mechanism, comprising aligned torque-transmitting members, a gear carried by one of said members, a jaw clutch element fixed on said one member, located within the periphery of said gear, a movable jaw clutch element drivingly associated with said other member, and axially slidable into positive clutching engagement with said fixed jaw clutch element, and a friction clutch member having a laterally flanged periphery overlying portions of the teeth of said gear, the said tooth portions being formed with friction clutching surfaces engageable with a coacting interior friction clutch face in said flanged periphery, and means for causing the friction clutch element to engage said gear teeth clutching surfaces when said movable clutch element is moved toward positive clutching position.

2. A synchronizer mechanism, comprising aligned torque-transmitting members, a gear carried by one of said members, said gear having an integral internal jaw clutch element disposed within its toothed periphery, a. movable jaw clutch element drivingly associated with said other member, and axially slidable into positive clutching engagement with said gear Jaw clutch element, and a friction clutch member having a laterally flanged periphery overlying portions of the teeth of said gear, the said tooth portions being formed with friction clutching surfaces engageable with a coacting interior friction clutch face in said flanged periphery, and means for causing the friction clutch element to engage said gear teeth clutching surfaces when said movable clutch element is moved toward positive clutching position.

JOHN M. SIMPSON. 

